The present invention relates to a method of inspecting various control functions of a differential apparatus with a limited slip differential mechanism, a traction control system, an anti-lock brake system (or anti-wheel-lock brake system) and the like of a motorcar.
Conventionally, there is known, in Japanese Published Unexamined Utility Model Registration Application No. 84544/1988, a method of inspecting various control functions of a differential apparatus with a limited slip differential mechanism, a traction control system, an anti-lock brake system and the like of a motorcar by using an inspecting apparatus which is provided with rolls for mounting thereon respective wheels of the motorcar.
This conventional method is arranged as follows. A judgement whether or not the differential apparatus with the limited slip differential mechanism is acceptable is made in the following manner, i.e., a starting and accelerating operation is performed in a condition in which a roll for mounting thereon one of the right and left driving wheels is braked, to see whether or not a value of increase in the rotational speed of the other of the driving wheels within a predetermined time falls within a predetermined set value which is defined by the limited slip differential mechanism. A judgement whether or not the traction control system is acceptable is made in the following manner, i.e., a starting and accelerating operation is performed in a condition in which the rolls for mounting thereon the driven wheels are stopped, to see whether or not a value of increase in the rotational speed of the driving wheels within a predetermined time falls within a set value which is defined by the traction control system. Further, in the inspection of the anti-lock brake system, each of the wheels is rotated on each of the rolls and, when the rotational speed of the wheels has reached a predetermined speed, each of the rolls is made to be independently rotatable. A judgement whether or not the anti-lock brake system is acceptable is then made in the following manner, i.e., a brake is applied in the above-described condition to see whether or not the braking time required to decelerate each of the wheels from a predetermined upper limit speed down to a predetermined lower limit speed falls within an allowable range.
In the above-described method, when the inspection of the differential apparatus with the limited slip differential mechanism has been finished by the starting and accelerating operation, the motorcar must be once returned to a stopped condition and then started and accelerated again to perform the inspection of the traction control system. It has therefore a disadvantage in that the inspection is time-consuming.
By the way, the differential apparatus with the limited slip differential mechanism functions to operate in the following manner. Namely, when one of the wheels races or slips, the driving force is distributed to the other of the wheels so that the difference in the rotational speeds of both wheels falls within a predetermined range. The apparatus thus has a function of accelerating at least one of the wheels.
The traction control system, on the other hand, functions to operate in the following manner. Namely, a ratio of slippage of the driving wheels is calculated based on the difference in rotational speeds between the driving wheels and the driven wheels and, when the ratio of slippage has increased, the output of the engine is controlled to decelerate the driving wheels.